The present invention relates generally to a bypass oil filtering system for an internal combustion engine, and more particularly to an adapter for connecting a bypass oil filter to an engine lubrication system while leaving the full flow filter in place.
In general, internal combustion lubrication systems operate on either a full flow or bypass principle. In full flow operation, the entire circulating oil stream is passed through the engine oil filter (referred to as a full flow oil filter) before it returns to the engine. In a bypass system, only a portion of the circulating oil stream is passed through the engine oil filter (referred to as a bypass oil filter) prior to being returned to the engine.
The full flow filter and the bypass filter each offer benefits not found in the other. The bypass oil filter will typically be more efficient and achieve a higher degree of contaminant removal than the full flow filter, but filters the oil less frequently. Conversely, the full flow filter filters the oil more often, but must use a relatively coarse filtering media in order to pass the entire volume of circulating oil required to lubricate the engine. Such a coarse media does not remove small contaminant particles, causing sludge deposits and contributing to engine wear. Moreover, as dirt accumulates in a full flow filter, the flow of oil is restricted. To prevent cessation of oil flow, the full flow filter system must be provided with a bypass valve that opens when the pressure drop across the full flow filter becomes excessive. The bypass valve allows oil to continue circulating, but such oil is not filtered at all.
While most automobile engines are equipped only with a full flow filtering system, many people desire to add on a bypass filter to enjoy the advantages associated with each system. Heretofore, bypass filters have been connected to full flow lubrication systems by means of an adapter placed between the full flow filter mounting block and the full flow filter itself. The oil is returned to the engine block typically by tapping the oil pan or by using a hollow bolt. The need to punch a hole in the oil pan or otherwise tamper with the engine block is undesirable and it would therefore be useful to provide an adapter having means both for supplying dirty oil to the bypass filter and returning the filtered oil to the engine.
2. Description of the Prior Art
A bypass oil filter is described in U.S. Pat. No. 3,308,956 to Yee, et al., an oil filter adapter for connecting a bypass filter to an internal combustion engine is disclosed in U.S. Pat. No. 3,540,594 to Sanderson.